Fix abstractmethod return

Author: Merricx

src/zkregex_fuzzer/runner/python.py

@@ -37,7 +37,7 @@ def match(self, input: str) -> tuple[bool, str]:
             raise RegexRunError(f"Error matching regex: {e}")
 
     def save(self, path: str) -> str:
-        return super().save(path)
+        return ""
 
     def clean(self) -> None:
-        return super().clean()
+        return None